/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: OneStepIteratorForward.java,v 1.2.4.2 2005/09/14 19:45:22 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMFilter;
import com.sun.org.apache.xpath.internal.Expression;
import com.sun.org.apache.xpath.internal.compiler.Compiler;
import com.sun.org.apache.xpath.internal.compiler.OpMap;

/**
 * This class implements a general iterator for
 * those LocationSteps with only one step, and perhaps a predicate,
 * that only go forward (i.e. it can not be used with ancestors,
 * preceding, etc.)
 * @see com.sun.org.apache.xpath.internal.axes#ChildTestIterator
 * @xsl.usage advanced
 */
public class OneStepIteratorForward extends ChildTestIterator {
    static final long serialVersionUID = -1576936606178190566L;
    /** The traversal axis from where the nodes will be filtered. */
    protected int m_axis = -1;

    /**
     * Create a OneStepIterator object.
     *
     * @param compiler A reference to the Compiler that contains the op map.
     * @param opPos The position within the op map, which contains the
     * location path expression for this itterator.
     *
     * @throws javax.xml.transform.TransformerException
     */
    OneStepIteratorForward(Compiler compiler, int opPos, int analysis) throws javax.xml.transform.TransformerException {
        super(compiler, opPos, analysis);
        int firstStepPos = OpMap.getFirstChildPos(opPos);

        m_axis = WalkerFactory.getAxisFromStep(compiler, firstStepPos);

    }

    /**
     * Create a OneStepIterator object that will just traverse the self axes.
     *
     * @param axis One of the com.sun.org.apache.xml.internal.dtm.Axis integers.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public OneStepIteratorForward(int axis) {
        super(null);

        m_axis = axis;
        int whatToShow = DTMFilter.SHOW_ALL;
        initNodeTest(whatToShow);
    }

    /**
     * Initialize the context values for this expression
     * after it is cloned.
     *
     * @param context The XPath runtime context for this
     * transformation.
     */
    public void setRoot(int context, Object environment) {
        super.setRoot(context, environment);
        m_traverser = m_cdtm.getAxisTraverser(m_axis);

    }

    //  /**
    //   * Return the first node out of the nodeset, if this expression is
    //   * a nodeset expression.  This is the default implementation for
    //   * nodesets.
    //   * <p>WARNING: Do not mutate this class from this function!</p>
    //   * @param xctxt The XPath runtime context.
    //   * @return the first node out of the nodeset, or DTM.NULL.
    //   */
    //  public int asNode(XPathContext xctxt)
    //    throws javax.xml.transform.TransformerException
    //  {
    //    if(getPredicateCount() > 0)
    //      return super.asNode(xctxt);
    //
    //    int current = xctxt.getCurrentNode();
    //
    //    DTM dtm = xctxt.getDTM(current);
    //    DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis);
    //
    //    String localName = getLocalName();
    //    String namespace = getNamespace();
    //    int what = m_whatToShow;
    //
    //    // System.out.println("what: ");
    //    // NodeTest.debugWhatToShow(what);
    //    if(DTMFilter.SHOW_ALL == what
    //       || ((DTMFilter.SHOW_ELEMENT & what) == 0)
    //       || localName == NodeTest.WILD
    //       || namespace == NodeTest.WILD)
    //    {
    //      return traverser.first(current);
    //    }
    //    else
    //    {
    //      int type = getNodeTypeTest(what);
    //      int extendedType = dtm.getExpandedTypeID(namespace, localName, type);
    //      return traverser.first(current, extendedType);
    //    }
    //  }

    /**
     * Get the next node via getFirstAttribute && getNextAttribute.
     */
    protected int getNextNode() {
        m_lastFetched = (DTM.NULL == m_lastFetched) ? m_traverser.first(m_context) : m_traverser.next(m_context, m_lastFetched);
        return m_lastFetched;
    }

    /**
     * Returns the axis being iterated, if it is known.
     *
     * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple
     * types.
     */
    public int getAxis() {
        return m_axis;
    }

    /**
     * @see Expression#deepEquals(Expression)
     */
    public boolean deepEquals(Expression expr) {
        if (!super.deepEquals(expr))
            return false;

        if (m_axis != ((OneStepIteratorForward) expr).m_axis)
            return false;

        return true;
    }

}
